I would like to suggest two features to consider for future development:

GraphicsMagick support: Better performance

WebP support: seems to be the new standard for reduced image files size - could be false, only time can tell so it should be a mid-term goal

What do you think about these suggestions? Would really like to hear what you have to say about the two points.

@nosilver4u: Have you thought about developing more openly on GitHub, yet? If you like the idea I am willing to help you make the transition. Have a look at my plans for a supporting service here: http://bit.ly/19xtLtT
I already helped move the Ajaxplorer repo to GitHub - Maybe you know the fantastic app.

GraphicsMagick support: not sure where this would be beneficial. It doesn't appear to support any sort of image optimization. The plugin only uses similar libs (GD & ImageMagick) to do image conversion. The real performance hit on conversion comes from the PNG optimizers. GD and ImageMagick are supported because pretty much everyone has one or both available on their web server. In short, I don't think GraphicsMagick will make it onto the roadmap unless we get a lot of interested folks to chime in.

WebP support: now this one looks interesting. The optimization claims are very impressive, but support is unfortunately limited to Chrome & Opera as far as I know. I definitely think this could be a long term goal. If others are interested in WebP, please post your +1 here.

Lastly, regarding GitHub, I'll have to decline. This is the only plugin I develop, and my needs are pretty simple. I don't have any knowledge of git, so it wouldn't benefit this project to move things to a new dev platform.

About GitHub:
- you can use your SVN tools on GitHub as well -> no real changes for you
- the community can contribute as lot easier

Although I am 100% sure that Git is far superior to SVN the whole GitHub environment is the great plus for all open source projects developed on it.
Please have a look at it and look up the benefits of pull requests and the easiness of forking repos on GitHub.